Bright copying hectograph blanket



July 1, 1941.; R Q' 2247 347 BRIGHT COPYING HECTOGRAPH BLANKET Filed Feb. 19, 1940 Patented July 1, 1941 UNITED STATES PATE BRIGHT COPYING HECTOGRAPH BLANKET Robert C. Bour, Chicago, 111., assignor to Ditto, Incorporated, Chicago, 111., a corporation of West Virginia Application February 19, 1940, Serial No. 319,698

FFIC

, Claims.

The invention relates to bright copying hectograph blankets.

An object of the invention is to provide hectograph pads of increased toughness, higher copying strength and freedom fromv sweating.

According to the application of William Hoskins, Jr., entitled Means for and method of dupli cating, filed December 20, 1939, Serial No. 310,108, the copy strengthrof hectograph blankets can be increased considerably by incorporating in the hectograph composition an oil such as a mineral oil or a glyceride of a fatty acid which is not (Ci. 41l31.6)

To illustrate the invention, the following for-' mulae of suitable hectograph compositions are given:

soluble in the constituents of .the hectograph Parts by weight mass. However, hectograph masses of this type have been known to sweat very considerably. 1 1 11 III IV v VI While this sweating does not render these hectograph blankets valueless, it is a feature which am so so so so so desirably should be eliminated. 5g 3g 13 3g 2?, 32 A primary object of the invention is, therefore, 1m i- 65 65 c5 as to provide an improved hectograph blanket over Egg gg;

the hectograph blankets described in the Hoskins Glycol stearate. 6

application Serial "Number slams. glgeg gg g 15 5 I have discovered that if an ester or a dihydric Glyool 5 alcohol such as glycol oleate, glycol stearate. and 011mm di-ethylene glycol laurate, is incorporated in the hectograph mass in quantities from about 2 to 15%, an appreciable increase in copy strength is achieved without objectionable sweating.

Other'obiects and advantages of the invention will become apparent as the following detailed description progresses, reference being had to the accompanying drawing wherein Fig. 1 is a sectional elevation of a hectograph 1 pad constituting a preferred embodiment of this invention; and

Fig. 2 is a sectional elevation of a modified hectograph pad.

In Fig. 1 of the drawing, the reference charac The ingredients are mixed together and heated in a water bath with vigorous agitation so that the glycol ester is emulsified or so finely dispersed in the composition that it will not settle out when standing; The dispersion so formed is coated on the backing and allowed to gel, forming the hectographblanket. The glycol ester is present in the gelled hectograph mass as the discontinuous phase of a colloid system. This system is sometimes called an oil in water type emulsion or oil in water type dispersion, depending upon whether the glycol ester is a liquid or a. solid.

Copies are prepared from the hectograph pad of the invention in the usual manner. A design is formed on a copy paper by writing or typing eliminated, however, with less satisfactory results.

with an ink made of water or alcohol soluble dyes. The design is then contacted with the gelatinous copy surface of the pad, whereupon the dye is largely transferred to the composition giving the design in mirror reverse. Copies are then made by contacting sheets of paper with the design on the hectograph copy mass. It will be found that a large number of copies of high color intensity can be obtained.

While it is not desired to be limited to any theory regarding the mechanism 01' the action giving the high color intensity, it is believed that the dyes deposited on the composition in the proc ess of duplicating-will be loosely bound bypowers of surface activity in the interphase between the dispersed water insoluble particles and the continuous phase of the hydrophilic composition. Therefore, the dye will be retained on or near the surface of the composition, thus being more readily available for copying purposes than would otherwise be the case.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Bubstitution of equivalent materials and changes in the proportions may be madewithout departing from the spirit and scope of the invention as described in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as possible, in view oi the prior art.

I claim:

1. A hectograph blanket comprising a copy mass of a hydrophilic gel containing a water insoluble ester of a dihydric alcohol.

2. A hectograph blanket comprising a backing having thereon a copy mass of a hydrophilic gel containing a water insoluble ester of a dihydric alcohol dispersed in the copy mass in the form of minute particles.

3. A hectograph blanket comprising a backing having thereon a copy mass of a hydrophilic gel containing glycol oleate dispersed in the copy mass in the form of particles of at least microscopic size.

4. A hectograph blanket comprising a backing having thereon a copy mass oi a hydrophilic gel containing glycol stearate dispersed in the copy mass in the form of particles of at least microscopic size.

5. A hectograph blanket comprising a backing having thereon a copy mass of a hydrophilic gel containing diethylene glycol laurate dispersed in the copy mass in the form of particles of at least microscopic size.

ROBERT C. BOUR. 

